Mathematical And Physical Simulation On120t RH Vacuum Refining Process

By increasing circulation flow rate and shortening mixing time, the RH productionrate can be increased in actual system. Therefore, in order to take full adcantage of theproduction efficiency of RH degasser and reduce production costs, we must have asufficient understanding of the flow and mixing characteristics of the RH degasser.Aiming at a steel plant120t RH refining furnace, the thesis systematically studied theflow and mixing characteristics of the RH degasser, using physical simulation andnumerical simulation method, and the process operation parameters are optimized.A water modeling with a linear scale of1:4for the RH degasser has beenestablished to have an insight into the flow and mixing characteristics in the RH process.The result shows that, the circulation flow rate increases with the increase of thedriving gas flow, insert depth, vacuum degree, aperture count increase and the decreaseof the productivity; the mixing time decreases with the increase of the driving gas flow,insert depth, vacuum degree, aperture count increasing and the increase of theproductivity; when the driving gas flow gets2.8m3/h, insert depth150mm, vacuumdegree3614pa, aperture counts12, the circulation flow rate reaches the maximum, themixing time gets the minimum.A3-dimesion mathematical model of molten steel flow in RH refing process hasbeen developed based on Eulerian-Eulerian Two-fluid Model and the InterphaseTransfer Model to calculate the flow field and the circulation flow rate of the device.The result shows that, the molten steel of the space between two dip pipe cannotcirculate effectively, it’s harmful for the mixing of molten steel; the original12holeaperture distribution is resonable, the blocking of aperture can significantly reduce thecirculation flow rate and the refining effect; the circulation flow rate increases with theincrease of the driving gas flow, insert depth and the decrease of the vacuum degree(theabsolute pressure in vacuum chamber), the driving gas flow has a appreciable impact,and the insert depth and vacuum degree impact is not obvious. According to the currentcalculation, when the driving gas flow gets92.3m3/h, insert depth600mm, vacuumdegree133pa, aperture counts12, the circulation flow rate reaches the maximum.